With rapid developments of display technique, touch panels have spread throughout people's daily life gradually. Generally, according to compositions and structures, touch panels can be divided into following modes: add on mode touch panels, on cell touch panels and in-cell touch panels. An add on mode touch panel is a liquid crystal display (LCD) with touch function which is formed by manufacturing a touch panel and a liquid crystal display separately and attaching the touch panel to the liquid crystal display. The add on mode touch panel has disadvantages, such as high manufacturing cost, low light transmittance, thick module etc. And in an in-cell touch panel, the touch electrode units of the touch panel are provided inside the liquid crystal display, which not only reduces an entire thickness of the module, but also reduces manufacturing cost of the touch panel greatly. Accordingly, the in-cell touch panel is popular to various major manufactures of panels.
In-cell touch panels generally employ principles of mutual-capacitance or self-capacitance to detect touch positions of fingers of a user. Principle of self-capacitance is to provide a plurality of electrode units in a touch layer, the electrode units are independent and insulated from each other and correspond to touch blocks, When human body does not touch the touch panel, capacitance which respective capacitance electrodes bears is a fixed value. When the human body touches the touch panel, it corresponds to connect a self-capacitor relative to ground to an electrode block in parallel, and a touch detection chip can detect change of capacitance value of a respective electrode block to decide a position touched by the human body.